Ionics最新文献

The development of high-performance and cost-effective electrocatalysts toward the oxygen evolution reaction (OER) is remarkably desirable but challenging. Herein, we design and fabricate a sea urchin-like S-doped Ni(OH)₂ electrocatalyst on nickel foam using a simple hydrothermal method, followed by treatment with Na₂S solution. The introduction of S not only modulates the electronic structure of Ni(OH)₂, but also improves the electronic conductivity, thus enhancing the OER performance of Ni(OH)₂. Owing to the free-standing feature, modified electronic structure, and sea urchin-like structure, the optimized S-Ni(OH)₂–30 min delivers excellent OER performance with overpotentials of 306 and 392 mV at 10 and 100 mA cm⁻², respectively, Tafel slope of 89.2 mV dec⁻¹, and stability for 30 h at 50 mA cm⁻². This work demonstrates the importance of incorporating S in Ni(OH)₂ to optimize the electronic structure for improving OER activity and provides a promising pathway to synthesize Ni(OH)₂-based electrocatalysts.

In this work, we used the unique monoclinic Zn₂P₂O₇heterostructure as an efficient electrode material for high-performance pseudocapacitors, and 2 M KOH as the electrolyte. We developed an effective two-step hydrothermal and polymerisation process to produce an uncommon heterostructure of Zn₂P₂O₇@PPy on 3D Ni foam. Remarkably, the Zn₂P₂O₇ NSs electrode that was synthesised demonstrated a high specific capacitance (SC) of 1246 F/g at 1 A/g and a high current loading of 10 A/g at 612 F/g. Furthermore, its robust long-term cycling performance at high current density was demonstrated by its retention of approximately 94.6% during continuous 10,000 charge–discharge cycles at a current density of 5 A/g. An asymmetric supercapacitor (ASC) with a maximum energy density of 92.4 Wh/kg and a power density of 1800 Wk/g is constructed using Zn₂P₂O₇/NF@PPy (ZNPP) as the cathode material.The improved capacitive storage of the ASC device may be attributed to the linked Nanosheet structure and the optimal combination of Polypyrrole.

Sodium-ion batteries are gaining attention as a viable alternative to lithium-ion batteries, primarily due to the widespread availability and affordability of sodium. However, the challenge of developing efficient cathode materials remains significant. In this study, we present an economical synthesis method to stabilize Na₃V₂(PO₄)₂F₃@C (NVPF@C) nanoparticles, which are encapsulated within a conductive reduced graphene oxide network (NVPF@C/rGO), serving as an advanced cathode material for sodium-ion batteries. The resulting structure features 50 nm nanoparticles encased in a carbon layer and intertwined with reduced graphene sheets, leading to improved electronic conductivity and better accommodation of volume changes during cycling. When used as a cathode in sodium-ion half-cells, the NVPF@C/rGO nanocomposite demonstrated an impressive reversible capacity of 130 mAh.g⁻¹ at a 0.5 C rate, along with exceptional cycling stability, maintaining 99% of its capacity after 500 cycles, and retaining a capacity of 115 mAh.g⁻¹ even at a high rate of 10 C. Detailed characterizations indicated that the graphene encapsulation not only supports efficient electron transport but also ensures reversible sodium storage by maintaining structural integrity. Moreover, the outstanding energy storage performance of the Na₃V₂(PO₄)₂F₃@C/rGO cathode material in full sodium-ion cell tests underscores its potential for practical applications.

Ordered mesoporous carbon–confined ZnO nanoparticles (OMC-ZnO) are prepared by a chelation-assisted co-assembly method. The SEM images indicate ZnO nanoparticles are embedded in the ordered mesoporous carbon. The lithiophilic ZnO served as nucleation sites that can homogenize lithium metal deposition. The ordered mesoporous carbon layers can increase the electronic conductivity and structural stability. As a result, the OMC-ZnO exhibits a significantly improved Coulombic efficiency of 98.5% over 400 cycles at 1 mA cm⁻². The OMC-ZnO/Li electrode obtained by electrodeposition delivers an outstanding cycling performance of over 1000 h and an ultralow voltage hysteresis of 14 mV in a symmetrical cell at 1 mA cm⁻² for 1 mAh cm⁻². Furthermore, the full cell paired with a LiFePO₄ cathode shows a steady Coulombic efficiency and high capacity up to 116.6 mAh g⁻¹ at 1 C after 700 cycles. This work can provide an innovative strategy to fabricate advanced hosts and solve the problem of Li metal batteries.

The world is gradually adopting electric vehicles (EVs) instead of internal combustion (IC) engine vehicles that raise the scope of battery design, battery pack configuration, and cell chemistry. Rechargeable batteries are studied well in the present technological paradigm. The current investigation model simulates a Li-ion battery cell and a battery pack using COMSOL Multiphysics with built-in modules of lithium-ion batteries, heat transfer, and electrochemistry. This model aims to study the influence of the cell’s design on the cell’s temperature changes and charging and discharging thermal characteristics and thermal runaway propagation characteristics of a battery and a battery pack composed of 18,650 and 4680 cylindrical batteries. The charge and discharge C-rates are varied. An event-based thermal runaway of the cell and a battery pack is presented finally. Based on the findings, it can be determined that the cell’s temperature is closely connected to the geometry of the cell, the C-rate, the active mass loading of the electrodes, and the operating temperature. For 18,650 and 4680 types, a projected capacity is 2.71 Ah and 21.8 Ah, heat generated is 1.19 Wh and 3.44 Wh, and the cell temperature at a constant discharge rate of 1C is 21.08 °C and 147.57 °C respectively. 4680 battery occupies four times less space, eight times less number of cells, and 20% less current collector materials utilized than the 18,650 battery, for a common capacity of 100 KWh.

Sodium-ion batteries (SIBs) are considered one of the most promising candidate technologies for future large-scale energy storage systems due to their highly abundant sodium and advantages similar to lithium-ion batteries (LIBs). However, the successful commercialization of SIBs relies heavily on the development of high-performance anode materials. Carbon-based materials are considered the ideal choice for SIBs negative electrode because of their abundant resources, cost-effectiveness, environmental friendliness, and excellent electrochemical properties. In this paper, the research progress of carbon anode materials in SIBs is reviewed. The application status of different carbon anode materials and the storage mechanism of four types of sodium ions in the hard carbon structure are systematically introduced and discussed. From the aspects of heteroatom doping, pore structure design, and layer spacing adjustment, this paper introduces the latest research progress in improving the sodium storage performance of carbon-based anode materials and summarizes the strategies for enhancing this performance. Finally, the future development directions and challenges of high-performance carbon-based anode materials are discussed and prospected, providing a feasible reference scheme for the rapid development of SIBs.

In this report, we have employed an electrodeposition approach under three-electrode configuration to fabricate Co₃O₄ electrode film and investigated the effect of electrolytic Na⁺ and K⁺ from KOH, NaOH, and Na₂SO₄ aqueous electrolytes, on its charge storage characteristics. The microstructural studies validated the formation of stable phases and cubic crystal structure. The film grew with slightly dense sphere-shaped nanostructure and large surface area and is composed of corresponding elements, as revealed from microstructural studies. The charge storage measurements on fabricated Co₃O₄ film electrode were carried out extensively under three-electrode mode. The electrode’s performance was found to be dependent on ion diffusion nature of the electrolytes and hence displayed optimum specific capacitance/capacity of 240 Fg⁻¹/46.6mAh g⁻¹ in Na₂SO₄ compared to in NaOH due to multiple redox peaks, with better ion diffusion in KOH due to smaller Na⁺ ions, constituting relatively low solution resistance with faster ion kinetic and transport. The study unveiled that the performance of Co₃O₄ electrode in aqueous electrolyte is dependent on the electrolyte’s ionic strengths, mobility and diffusion, and pH.

Hydrogen fuel is a promising sustainable energy source, offering a clean alternative to fossil fuels. This study investigates the potential of plasma-sprayed barium titanate (BaTiO₃) coated graphite electrodes to enhance hydrogen production through water electrolysis. Characterization techniques, including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), electrical resistivity measurements, porosity and corrosion resistance assessments, were used to evaluate the performance of both uncoated and BaTiO₃-coated electrodes. The results confirm a uniform 50 µm BaTiO₃ coating, free of impurities, that significantly reduces electrode resistivity and increases surface area, facilitating improved hydrogen evolution. The BaTiO₃-coated electrodes demonstrated a 57.24% improvement in hydrogen production efficiency in alkaline conditions and 62.85% in acidic conditions, along with enhanced corrosion resistance. These findings highlight the potential of BaTiO₃ coatings to advance hydrogen fuel technology by increasing production efficiency and electrode durability in electrolysis systems.

Aqueous Zn/MnO₂ batteries have extensively attracted attentions for their superior comprehensive performance. However, the poor structural stability and dissolution of MnO₂ have seriously prevented its further development. Therefore, TiO₂ is introduced for coating MnO₂ to improve its electrochemical stability. Firstly, TiO₂ used as a protective layer could hamper the direct contact between the electrode and the electrolyte, and effectively inhibiting the dissolution of manganese. Secondly, TiO₂ has good mechanical strength to alleviate to the volume change of MnO₂ during the charge/discharge processes, which consolidates the stability of the electrode material. Finally, TiO₂ could improve the electrical conductivity of the composite material, achieving lower polarization and good electron/ion transport. As a result, Zn/MnO₂@TiO₂-2 exhibits extraordinary electrochemical performance with a rate capacity of 245.16 mAh g⁻¹ at 0.2 A g⁻¹ and maintains a capacity of 137.09 mAh g⁻¹ after 1000 cycles at 1 Ag⁻¹. Even at a high current density of 3 A g⁻¹, it has a capacity of 93.35 mAh g⁻¹ after 1500 cycles, and the capacity retention rate is 97.47%. This work provides the inspiration and foundation method for designing high-performance Zn/MnO₂ batteries.

Lithium iron phosphate (LiFePO₄) is emerging as a key cathode material for the next generation of high-performance lithium-ion batteries, owing to its unparalleled combination of affordability, stability, and extended cycle life. However, its low lithium-ion diffusion and electronic conductivity, which are critical for charging speed and low-temperature performance, have become the primary constraints on its broader application. This study addresses these challenges by investigating the impact of Mn, Ti, and V doping on the low-temperature discharge characteristics of LiFePO₄. The article presents the synthesis of LiFe_0.95V_0.05PO₄, LiFe_0.95Ti_0.05PO₄, and LiFe_0.95Mn_0.05PO₄, which have demonstrated impressive discharge capacities of 88%, 80%, and 76% at − 20 °C compared to their performance at 25 °C. The vanadium doping strategy has been found to encourage the spherical growth of lithium iron phosphate material, resulting in nano-spherical particles with a balanced transverse and longitudinal growth rate. This growth pattern is attributed to the interplay between the “Mosaic models” and “Radial models” of lithium ion diffusion. The electronic and ionic transport properties have been analyzed using density functional theory, revealing that it possesses low formation energy at the Fe site. This characteristic allows for stable doping at the Fe site, leading to the formation of Mn–O, Ti–O, and V–O chemical bonds. The doping with vanadium significantly lowers the migration energy barrier and activation energy for lithium ions, thereby enhancing their transmission rate. These findings indicate that vanadium doping is an effective strategy to improve the low-temperature discharge performance of LiFePO₄ cathode materials.